How Our Engineering Team Works With You

Coi Rubber has over 23 years of experience in engineering, design, compounding, prototyping and production of molded rubber and plastic parts. Our Product Design and Engineering team combines mechanical engineering with knowledge of rubber and plastic materials, mold making and testing. We start at the design stage, so the part you draw can also be made well.

Design for manufacturability

We review your drawing for performance and for how it will be molded. We check that the part can meet real-world demands, and we make drawings that work with your systems. The team has specialist experience in molded hoses, shaft seals, surfacing products and vibration-control products. See our rubber product design guidelines, tolerance factors for molded rubber and how tight a tolerance you really need. Our RMA tolerance tables are available to review.

Material selection and compounding

We help you choose rubber and plastic materials based on the physical, chemical and thermal needs of the application. Materials we work with include natural rubber, SBR, EPDM, neoprene, NBR and thermoplastic elastomers (TPE, TPV, TPU). We mix our compounds in house and test them in our in-house lab. Learn more on our material technology page, in our durometer guide and in our ASTM rubber guidelines.

Rapid tooling and prototyping

Once the design is ready, our rapid tooling team can produce prototype parts and sample one-off tooling. Rapid tooling is done in China, with a typical lead time of 15 days.

Molding processes

• Compression molding: suited to low to medium volumes, large parts and costly compounds. Tooling can be simpler and lower cost, with less material lost to runners. At our Wuhu, China facility we run a 72 x 72 in press, a 54 x 60 in press and several smaller presses.
• Injection molding (including liquid silicone): suited to larger runs of small to medium parts, metal inserts and thin-wall diaphragms, with no preform step. Clamping pressure ranges from 300 to 1000 tons.
• Transfer molding and rubber-to-metal bonding: see the process pages for details.

See the full equipment list and our capabilities.

Quality and testing

Our Wuhu, China manufacturing facility is IATF 16949 certified. For automotive programs we provide PPAP Level 3 documentation. Read more on our quality assurance page.

What to send for a quote

To get an accurate quote, send an engineering drawing (a 2D print or 3D file), the material with a hardness call-out (for example “EPDM Rubber 60 +/- 5 Shore A”), and your estimated annual usage. Please show color, test standards, tolerances and key characteristics on the drawing. Our guide How To: Get a Quote for Rubber explains each item.

Request a Quote

Or email sales@coirubber.com or call (626) 965-9966.